Data supporting a role for HIPK2 as tumor suppressor have been obtained in mice where the hipk2 gene behaves as a haploinsufficient tumor suppressor in γ-irradiation-induced thymic lymphomagenesis [18], and in humans, where HIPK2 has been found inactivated by different mechanisms in different cancer types [19–21]. This evidence concerns the gene HIPK2 and neoplasm.